<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title>五彩导航</title>
		<style>
			ul li{
				width: 100px;
				height: 50px;
				border: 1px solid black;
				display: inline-block;
			}
			ul li a{
				text-align: center;
				line-height: 50px;
				text-decoration: none;
			}
			ul li:nth-child(1){
				background-image:url(img/bg1.png);
			}
			ul li:nth-child(2){
				background-image:url(img/bg2.png);
			}
			ul li:nth-child(3){
				background-image:url(img/bg3.png);
			}
			ul li:nth-child(4){
				background-image:url(img/bg4.png);
			}
			
			ul li:nth-child(1):hover{
				background-image: url(img/bg4.png);
			}
			ul li:nth-child(2):hover{
				background-image: url(img/bg1.png);
			}
			ul li:nth-child(3):hover{
				background-image: url(img/bg6.png);
			}
			ul li:nth-child(4):hover{
				background-image: url(img/bg7.png);
			}
			
		</style>
	</head>
	<body>
		<ul>
			<li><a href="#">五彩导航</a></li>
			<li><a href="#">五彩导航</a></li>
			<li><a href="#">五彩导航</a></li>
			<li><a href="#">五彩导航</a></li>
		</ul>
	</body>
</html>
